Australocosmica crassicostata n. sp.

Figs 3 C, 4D–E, 6C

Holotype. Australia, WA, Kimberley, Bonaparte Archipelago: Sta. KC-047, unnamed island between Maret and Berthier Is., -14.481, 125.004 (coll. V. Kessner, A. Longbottom, 15 July 1988) (WAM S84059). Paratypes. Australia, WA, Kimberley, Bonaparte Archipelago: same data as for holotype, 2 wet (WAM S83036), 4 wet (FMNH 219201), 8 dry (WAM S83035), 9 dry (FMNH 219200); Sta. KC-044, Berthier Island, SW corner island, - 14.513, 124.981 (coll. V. Kessner, A. Longbottom, 14 July 1988), 1 dry (WAM S83030), 1 dry (FMNH 219173); Sta. KC-045, North Maret Island, -14.399, 124.973 (coll. V. Kessner, A. Longbottom, 15 July 1988), 32 dry (WAM S83031), 31 dry (FMNH 219180); Sta. KC-045, North Maret Island, -14.399, 124.973 (coll. V. Kessner, A. Longbottom, 15 July 1988), 53 wet (WAM S83032), 52 wet (FMNH 219181); Sta. KC-046, South Maret Island, - 14.441, 124.977 (coll. V. Kessner, A. Longbottom, 15 July 1988), 4 dry (WAM S83033), 4 dry (FMNH 219193); Sta. KC-046, South Maret Island, -14.441, 124.977 (coll. V. Kessner, A. Longbottom, 15 July 1988), 2 wet (WAM S83034), 1 wet (FMNH 219194); Sta. KC-048, N end of Berthier Island, -14.503, 124.986 (coll. V. Kessner, A. Longbottom, 15 July 1988), 1 dry (WAM S83037), 1 dry (FMNH 219207).

Etymology. In reference to the shell sculpture, derived from “ crassus ” (Latin = thick, pronounced) and “ costatus ” (Latin = ribbed), adjective of feminine gender.

Description. Shell (Figs. 3 C; 4D, E). Diameter average, spire elevated and broadly conical shape. Whorls with slightly angulate periphery, moderately shouldered underneath suture. Axial ribs strong. Colour horn to light brown. Genitalia (Fig. 6 C). Penis about half as long as anterior part of oviduct (= vagina and free oviduct). Inner penial wall supporting complex sculpture, posteriorly with series of corrugated folds and diverticula, anteriorly with longitudinal folds extending into atrium. Vaginal length about three quarters of length of penis and free oviduct. Spermoviduct about 2.5 times longer than free oviduct and about twice as long as albumen gland.

Remarks: Shell colour as variable as in A. nana . On average shell smaller than A. augustae, A. rotunda and A. sanctumpatriciusae, larger than other congeners; more elevated and with more whorls than other congeners except A. augustae and A. pallida . Sculpture with fewer but more pronounced axial ribs than any other congener. Inner penial wall similar to that of A. rotunda with weaker posterior longitudinal pilasters.This is Solem’s (1991) manuscript species ‘NSP 79’. The distribution of A. crassicostata is not included in Köhler’s (2011: Fig.1) map having it mixed-up with ‘NSP 78’ (= A. bernoulliensis) (see above).